<template>
    <div class="header">
      <!-- 系统logo -->
      <div class="logo">
        <img src="@/assets/img/header.png" style="height: 40px; padding-bottom: 10px;"/>
        <span>后台管理系统</span>
      </div>
      <!-- 水平一级菜单 -->
      <div style="float:left; margin-left: -40px;">
        <el-menu mode="horizontal" text-color="#000000" active-text-color="#3989fa" :default-active="toIndex" @select="handleSelect">
          <el-menu-item v-for="(item, index) in menuList" :index="item.path" :key="index">
            <span slot="title">{{ item.title }}</span>
          </el-menu-item>
        </el-menu>
      </div>

      <div class="header-right">
        <div class="header-user-con">
          <!-- 切换主题 -->
          <div @click="handleChangeStyle()">
            <el-tooltip content="切换主题" placement="bottom">
              <i :class="globalTheme ? 'el-icon-moon' : 'el-icon-sunny'"></i>
            </el-tooltip>
          </div>
          <!-- 用户头像 -->
          <div class="user-avator">
            <img src="@/assets/img/header.png"/>
          </div>
          <!-- 用户名下拉菜单 -->
          <el-dropdown class="user-name" trigger="click" @command="handleCommand">
            <span class="el-dropdown-link"> {{ username }} <i class="el-icon-caret-bottom"></i></span>
            <el-dropdown-menu slot="dropdown">
              <el-dropdown-item disabled>修改密码</el-dropdown-item>
              <el-dropdown-item command="loginout">退出登录</el-dropdown-item>
            </el-dropdown-menu>
          </el-dropdown>
        </div>
      </div>
    </div>
</template>

<script>
  export default {
    name: "HeadMenu",
    data(){
      return{
        // 头部一级菜单
        menuList: [
          { path: '/index', title: '首页' },
          { path: '/system', title: '系统管理' },
        ],
        globalTheme: false,
      }
    },
    computed: {
      username(){
        return localStorage.getItem('ms_username') || 'admin';
      },
      toIndex(){  // 根据路径绑定到对应的一级菜单，防止页面刷新重新跳回第一个
        return '/' + this.$route.path.split('/')[1];
      },
    },
    created() {
      this.globalTheme = JSON.parse(localStorage.getItem('global_theme'));
      // bus.$emit('global_theme', this.globalTheme);  // 将 globalTheme 的值传给父组件
    },
    methods: {
      handleSelect(path){  // 切换菜单栏
        this.$router.push({
          path: path
        });
      },
      handleCommand(command){  // 用户名下拉菜单选择事件
        if(command === 'loginout'){
          localStorage.removeItem('ms_username');
          this.$router.push({
            path: '/Login'
          });
        }
      },
      handleChangeStyle(){  // 切换主题
        this.globalTheme = !this.globalTheme;
        localStorage.setItem('global_theme', this.globalTheme);  // 本地存储选择的 globalTheme
        // bus.$emit('global_theme', this.globalTheme);  // 将 globalTheme 的值传给父组件
      }
    }
  }
</script>

<style scoped>
  .header {
    position: relative;
    box-sizing: border-box;
    width: 100%;
    height: 70px;
    font-size: 22px;
    background: white;
  }
  .header .logo {
    float: left;
    width: 220px;
    vertical-align: middle;
    display: flex;
    align-items: center; /* 垂直居中 */
    justify-content: center; /* 水平居中 */
    height: 70px;
    //background: #b9cde2;
  }
  /* --------------- 用户头像区域的样式 ---------------- */
  .header-right {
    float: right;
    padding-right: 50px;
  }
  .header-user-con {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 70px;
  }
  .user-avator {
    margin-left: 20px;
  }
  .user-avator img {
    display: block;
    width: 40px;
    height: 40px;
    border-radius: 50%;
  }
  .user-name {
    margin-left: 10px;
  }
  .el-dropdown-link {
    cursor: pointer;
  }
  .el-dropdown-menu__item {
    text-align: center;
  }
  /* --------------- 水平一级菜单栏的样式--------------------- */
  .el-menu.el-menu--horizontal {
    border-bottom: none !important;
    float: left;
    margin-left: 50px;
    background: transparent;
  }
  .el-menu--horizontal > .el-menu-item.is-active {
    /* border-bottom: 2px solid #3989fa;
    color: #3989fa; */
    font-weight: bold;
  }
  .el-menu--horizontal > .el-menu-item {
    font-size: 16px;
    margin: 0 15px;
  }
</style>
